N-Glycan on the Non-Consensus N-X-C Glycosylation Site Impacts Activity, Stability, and Localization of the Sd Synthase B4GALNT2. - Université de Lille Accéder directement au contenu
Article Dans Une Revue International Journal of Molecular Sciences Année : 2023

N-Glycan on the Non-Consensus N-X-C Glycosylation Site Impacts Activity, Stability, and Localization of the Sd Synthase B4GALNT2.

Résumé

The Sd carbohydrate epitope and its biosynthetic B4GALNT2 enzyme are expressed in the healthy colon and down-regulated to variable extents in colon cancer. The human gene drives the expression of a long and a short protein isoform (LF-B4GALNT2 and SF-B4GALNT2) sharing identical transmembrane and luminal domains. Both isoforms are trans-Golgi proteins and the LF-B4GALNT2 also localizes to post-Golgi vesicles thanks to its extended cytoplasmic tail. Control mechanisms underpinning Sd and B4GALNT2 expression in the gastrointestinal tract are complex and not fully understood. This study reveals the existence of two unusual -glycosylation sites in B4GALNT2 luminal domain. The first atypical N-X-C site is evolutionarily conserved and occupied by a complex-type -glycan. We explored the influence of this -glycan using site-directed mutagenesis and showed that each mutant had a slightly decreased expression level, impaired stability, and reduced enzyme activity. Furthermore, we observed that the mutant SF-B4GALNT2 was partially mislocalized in the endoplasmic reticulum, whereas the mutant LF-B4GALNT2 was still localized in the Golgi and post-Golgi vesicles. Lastly, we showed that the formation of homodimers was drastically impaired in the two mutated isoforms. An AlphaFold2 model of the LF-B4GALNT2 dimer with an -glycan on each monomer corroborated these findings and suggested that -glycosylation of each B4GALNT2 isoform controlled their biological activity.
Fichier principal
Vignette du fichier
ijms-24-04139-v2.pdf (5.04 Mo) Télécharger le fichier
Origine Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-04257639 , version 1 (25-10-2023)

Licence

Identifiants

  • HAL Id : hal-04257639 , version 1
  • PUBMED : 36835549

Citer

Virginie Cogez, Dorothee Vicogne, Celine Schulz, Lucie Portier, Giulia Venturi, et al.. N-Glycan on the Non-Consensus N-X-C Glycosylation Site Impacts Activity, Stability, and Localization of the Sd Synthase B4GALNT2.. International Journal of Molecular Sciences, 2023, International journal of molecular sciences, 24. ⟨hal-04257639⟩

Collections

CNRS UNIV-LILLE
13 Consultations
9 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More